<html>
    <head>
        <title>Pre-generated keyframes performance</title>
        <!--
      This file demonstrates that the performance of pre-generated keyframes is poor in Chrome
      under surprising circumstances.
      Specifically, pre-generated keyframes are fine in isolation. But when combined with a
      requestAnimationFrame animation, AND another WAAPI animation, performance becomes 
      (literally) 100x worse.
      To use:
      1. Open this file in Chrome
      2. Open performance tab and throttle 6x
      3. On an M1 Pro notice style recalculations of ~170ms
      4. Comment `animation.ready` block, disabling requestAnimationFrame animation
      5. Profile and notice style recalculations of ~1.5ms
      6. Undo changes 
      7. Comment out `opacity` WAAPI animation, moving `const animation = ` to background-color animation.
      8. Profile and notice style recalculations of ~2.5ms
      9. Undo changes 
      10. Replace `backgroundColor: pregeneratedKeyframes` with `backgroundColor: ["#f00", "#00f"]`
      11. Profile and notice style recalculations of ~2.5ms
    -->
        <style>
            body {
                display: flex;
                flex-wrap: wrap;
                gap: 10px;
                height: 100vh;
                overflow: hidden;
            }

            .box {
                width: 50px;
                height: 50px;
                background-color: #f00;
                opacity: 0;
                will-change: auto !important;
            }
        </style>
    </head>
    <body>
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        <script type="module" src="/src/imports/framer-motion-dom.js"></script>
        <script type="module">
            const boxes = document.querySelectorAll(".box")
            let startTime = 0
            const duration = 10000
            const rotateRate = 360 / duration

            function rotate(timestamp) {
                const elapsed = timestamp - startTime
                boxes.forEach((box, index) => {
                    box.style.transform = `rotate(${elapsed * rotateRate}deg)`
                })

                requestAnimationFrame(rotate)
            }

            function animateRotation() {
                startTime = performance.now()
                requestAnimationFrame(rotate)
            }
            // animateRotation()

            Motion.animate(
                boxes,
                { opacity: [0, 1], backgroundColor: ["#f00", "#00f"] },
                { duration: duration / 1000, repeat: Infinity }
            )
        </script>
    </body>
</html>
